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authorDimitri Sivanich <sivanich@sgi.com>2009-06-23 12:37:04 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2009-07-02 16:50:33 -0700
commitf4c28b780c88c1d12e740a9b0b67b9375b173960 (patch)
treedddffca051de3bbf989b9cd27d3316f3ffb5b7e1
parent74bd077eee9556d08bc37349da041f5c67903a7d (diff)
mm: fix handling of pagesets for downed cpus
commit 364df0ebfbbb1330bfc6ca159f4d6020efc15a12 upstream. After downing/upping a cpu, an attempt to set /proc/sys/vm/percpu_pagelist_fraction results in an oops in percpu_pagelist_fraction_sysctl_handler(). If a processor is downed then we need to set the pageset pointer back to the boot pageset. Updates of the high water marks should not access pagesets of unpopulated zones (those pointer go to the boot pagesets which would be no longer functional if their size would be increased beyond zero). Signed-off-by: Dimitri Sivanich <sivanich@sgi.com> Signed-off-by: Christoph Lameter <cl@linux-foundation.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--mm/page_alloc.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index fe753ecf2aa..f82038391ca 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2812,7 +2812,7 @@ bad:
if (dzone == zone)
break;
kfree(zone_pcp(dzone, cpu));
- zone_pcp(dzone, cpu) = NULL;
+ zone_pcp(dzone, cpu) = &boot_pageset[cpu];
}
return -ENOMEM;
}
@@ -2827,7 +2827,7 @@ static inline void free_zone_pagesets(int cpu)
/* Free per_cpu_pageset if it is slab allocated */
if (pset != &boot_pageset[cpu])
kfree(pset);
- zone_pcp(zone, cpu) = NULL;
+ zone_pcp(zone, cpu) = &boot_pageset[cpu];
}
}
@@ -4501,7 +4501,7 @@ int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
ret = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
if (!write || (ret == -EINVAL))
return ret;
- for_each_zone(zone) {
+ for_each_populated_zone(zone) {
for_each_online_cpu(cpu) {
unsigned long high;
high = zone->present_pages / percpu_pagelist_fraction;